Diffractive optical elements or DOEs are precision optical elements which are used in laser printers to form any desired quantity of output beam with a controlled separation between them. They can be formed in different forms such as crystals, micro-spheres, spheroids and lens fibers. They can also be made out of thin materials like plastic, paper and carbon sponges. There is a great demand for these devices in various sectors of industries. This article discusses various uses of diffractive optical elements.
These diffractive optical elements have very high separation between beams. This enables the end to be focused at a sharp spot without losing the complete image or color. They are mainly used in dye-sublimation printing in which there is need to change the color of the braid on the screen or ribbon used to make the ink. In this process, the droplets of dye are grown in a chamber under a certain amount of pressure and then extracted from it through a fiber-optic tube with a very high index of refraction. The resulting rays are then focused by using a ray head consisting of diffractive optical elements between them.
In various manufacturing processes, the output from the machine is in the form of streams of colors depending upon the requirement of the job. To carry out the job completely, special type of tools known as streamlining beam shapers are required which are made up of several micro-spheres or crystals attached to a common base and work as a single unit. They can be further divided into two groups namely, single-use ray beam splitters and multiple-use stream line beam shapers. The former has to be calibrated time and again while the latter may be used more frequently for the purpose of accomplishing more jobs.
Diffractive optical elements are used in several applications including laser systems. They have found tremendous use in the industry for carrying out various tasks related to illuminating a surface. They also play an important role in industrial welding and are extensively used in CIGS machines. They are also used in medical lasers to obtain accurate intensity control and focus.
Different methods are applied for the purpose of shaping diffractive optics. One such technique involves the application of wavefront shaping material, which is made up of diamond chips that is placed over a metal surface. This is done so as to modulate and control the intensity of laser beams. After shaping, the residual wavefront is sprayed onto the surface to be treated. This is done so as to reduce scattering and increase the focus of the laser beams.